CAPE CANAVERAL, Fla. — A pair of rookie Russian cosmonauts and a veteran U.S. astronaut arrived at the International Space Station on Thursday, boosting the crew back to full strength and bringing along 32 Japanese medaka fish.

After making sure seals between the two spacecraft were airtight, the men joined space station commander Sunita Williams, Japanese astronaut Akihiko Hoshide and cosmonaut Yuri Malenchenko to return the station to its full, six-member crew.

"It is so great to see all six of you on orbit and to see your smiling faces," William Gerstenmaier, NASA associate administrator for spaceflight, radioed to the crew from the Russian mission control near Moscow.

Ford, who flew as the pilot on a 2009 space shuttle mission, said he noticed different noises and vibrations riding on the Soyuz, but he found the trip just as enjoyable.

"The two days went really quickly," Ford told family and friends gathered at the Russian mission control during a televised welcoming ceremony. "It was an incredible ride."

Ford's Russian colleagues, both of whom are flying for the first time, had a bit of struggle adjusting to the weightless environment of space.

"I have to admit it was a little bit difficult the first day, but then it got better and easier," one of the cosmonauts said through a translator.

"It got tolerable," the other added. "Today, we're feeling great."

One of the first orders of business was transferring 32 Japanese medaka fish from special containers aboard the Soyuz into Japan's Kibo laboratory, where aquariums have been set up for a variety of experiments.

"The fish are still alive. Aki already has checked on them. He was very worried that they make it here," one of the cosmonauts said, referring to Hoshide.

The crew will have a busy schedule in the coming days. On Sunday, the privately owned Dragon cargo ship, which arrived at the station on Oct. 10, is due to depart.

The Space Exploration Technologies' freighter, making the first of 12 supply runs under a $1.6 billion NASA contract, will be returning with more than one ton (907 kg) of science experiments and gear from the orbital outpost, the first big load of cargo to come back to Earth since the space shuttles stopped flying more than a year ago.

The astronauts also are preparing for the arrival of a Russian cargo ship on Wednesday and a spacewalk the following day by Williams and Hoshide to try to repair a leak in a station cooling system.

Williams, Hoshide and Malenchenko are scheduled to return to Earth on Nov. 12, leaving the three newcomers on their own until replacements arrive on Dec. 21.